Apparatus for ejecting a mixture of liquids



Aug. 2, 1966 F. E. GUSMER APPARATUS FOR EJECTING A MIXTURE OF LIQUIDS Filed Nov. 19, 1964 R M N S U G E K m R E D E R F E 9 7 5 G FF ATTOR NEYS.

United States Patent 3,263,928 APPARATUS FOR EJECTING A MIXTURE 0F LIQUIDS Frederick E. Gusmer, 224 Watchung Fork, Westfield, NJ. Filed Nov. 19, 1964, Ser. No. 412,423 12 Claims. (Cl. 239-123) The present invention relates to apparatus for ejecting a mixture of liquids, and more particularly to ejecting a homogeneous mixture of liquids which must be mixed as nearly concurrently with ejection as possible. The invention has utility in a number of fields, such as the spraying of foam, the spraying of highly exothermic mixtures, and the spraying of thermosetting resin formulations. It will be disclosed, by way of example, in connection with the spraying of foam, particularly foam of the urethane type.

The term spraying as used herein is merely a shorthand designation for the ejection of the liquid mixtures. For most applications, the present invention will be used to eject mixtures in a divided form such as spray or droplets or larger cohesive units. However, it is to be understood that the present invention is also useful for the ejection of mixed liquids in a continuous stream.

It is also to be understood that although most of the ejection of mixed liquids according to the present invention will be against a solid substrate, it is also within the purview of the present invention to eject mixed liquids into a partially or completely enclosed region such as a chamber. Thus, the present invention is amenable to such applications as spray coating on a solid substrate, caulking by injection of a continuous stream into a joint or seam or the like, the insertion of insulation by the ejection of a continuous or particulate stream into a space to be insulated, the formation of shaped bodies of foamed or unfoamed plastics by eject-ion of a mixture of liquids into a mold cavity, the formation of unshaped bodies of foamed plastics by ejection of the mixture onto a moving conveyor, or other processes which will be obvious to persons having ordinary skill in this art.

In the past, great difficulty has been encountered in efforts to eject mixtures of liquids, particularly those liquids which undergo rapid change in the presence of each other, by virtue of exothermic reaction or short set-up time or for other similar reasons. In my Patent No. 2,890,836, June 16, 1959, I provided an apparatus for applying a mixture of a plurality of liquids, which was characterized by a mixing chamber having a plurality of inlets, the mixing chamber being adapted to be alternately opened and closed by a reciprocating plunger. The device of my earlier patent was a great-advance over the prior art and made possible for the first time the homogeneous mixture of a plurality of liquids virtually concurrently with their ejection from the mixing chamber, and also the substantially complete purging of the mixing chamber upon discontinuance of operation. In this way, it was possible to obtain uniform mixtures of liquids, and it was possible at the same time to avoid the need for frequently cleaning the equipment.

The present invention is partly an improvement on my earlier device, and partly an embodiment of new principles which achieve new results in relatively new fields of application of this type of equipment.

Specifically, it is an object of the present invention to provide an apparatus for ejecting a mixture of a plurality of liquids, in which a desirably large droplet size may be produced at the same time that homogeneous mixing is achieved.

Another object of the present invention is the provision of such apparatus in which the ejected mixed material is subject to relatively little ambient thermal effect, so that Patented August 2, 1966 the material can be ejected through an atmosphere of any desired temperature, or onto a substrate of any desired temperature within a wide range.

Still another object of the present invention is the provision of such apparatus that is especially well adapted to eject foamed or foaming mixtures of liquids. In this connection, it is more particularly an object of the present invention to provide apparatus Well adapted for ejecting urethane foams.

Moreover, it is an object of the present invention to provide such apparatus which is readily self-cleaning.

Finally, it is an object of the present invention to provide apparatus for ejecting a mixture of a plurality of liquids, which will be relatively simple and inexpensive to manufacture, easy to operate, maintain, clean and repair, and which will be rugged and durable in use.

Other objects and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawing, in which:

FIGURE 1 is a side elevation of apparatus according to the present invention, in the form of a spray gun;

FIGURE 2 is an enlarged cross-sectional view of the valve and ejector outlet assembly of the present invention;

FIGURE 3 is a cross-sectional view taken on the line 3-3 of FIGURE 2;

FIGURE 4 is a further enlarged perspective exploded assembly view of the valve barrel of the present invention; and

FIGURE 5 is a view similar to FIGURE 2 but showing a modified form of the present invention.

Referring now to the drawing in greater detail, there is shown a spray gun indicated generally at 1, and including a spray head 3. A valve housingS is removably secured in spray head3, and conduits 7 and 9 each supply a different liquid to spray head 3 for mixture in and ejection-from valve housing 5. Sources of supply for these different liquids under pressure to conduits 7 and 9 are no-t'shown but may take any of the forms of my earlier patent referred to above or the prior art in this field. An air hose 11 supplies compressed air to an air cap 13 that surrounds valve housing 5. Air cap 13 directs air against and along the exterior of valve housing 5 for the purpose of cleaning the front end of the spray appara-tus. For this purpose, compressed air can be used at relatively low pressure, for example, about 1 p.s.i.g. In this way, the accumulation of deposits of sprayed material about the outlet of the spray equipment is avoided.

A plunger 15 is reciprooable in valve housing 5. The plunger 15 adjacent its forward or free end is of cylindrical contour and of uniform external diameter. Adjacent its rear end, plunger 15 carries an'adjustment nut 17 screw-threadedly thereon. A coilcompression spring 19 bears between adjustment nut 17 and the rear end of a housing 21 carried by the spray gun and continuously urges plunger 15 forwardly. A piston 23 is slidable in a cylinder formed in the rear of the gun. A hollow tubular sleeve 25 extends forwardly from piston 23 and encompasses plunger 15 to guide and support plunger 15 and also to guide piston 23.

An air hose 27 under the control of valve 29 brings compressed air to the forward side of piston 23 to force piston 23 rearwardly against adjustment nut 17 and to force adjustment nut l17 and with it plunger 15 rearwardly against the action of spring 19. Valve 29 is selectively opened and closed by actuation of an actuating button 31 carried by the handle 33 of the spray gun. Depressing button 31 opens valve 29 to admit compressed air 27 to the chamber forwardly of piston 23, to drive the piston rearwardly until the rear end of plunger 15 contacts an adjustable plunger stop 35 screw-threadedly received in the rear of housing 21 and rotatably adjustable to advance or retract its forward end thereby to fix the rearmost position of plunger 15. The forwardmost position of plunger v15 is set by manipulation of adjustment nut 17.

The forward end of plunger I15 is disposed in a mixing chamber 37 within valve housing 5. Mixing chamber 37 has an outlet end 39 and is of substantially uniform cross-sectional configuration from end to end thereof, including outlet end 39. In general, it is preferred that mixing chamber 37 and outlet end 39 thereof have a uniformly cylindrical shape.

To this end, valve housing of the present invention comprises a barrel 41 machined with a generally cylindrical internal cavity and terminating at its forward end in a conical flange 43 the least internal diameter of which is of the diameter of mixing chamber 37 and which defines the forward or outlet end 39 of mixing chamber 37. Spaced rearwardly of outlet end 39 and rearwardly of conical flange 43 is a pair of inlet openings 45 and 47 that extend through the side walls of barrel 41 and that are not diametrically opposed to each other but rather are displaced from each other somewhat toward tangential relationship with chamber 37, as can best be seen in FIGURE 3.

Within its internal cavity, barrel 41 carries a pair of axially spaced packing sleeves 49 of cylindrical outer contour and cylindrical inner cont-our, the cylindrical inner contours of which define a portion of mixing chamber 37. The forward packing sleeve 49 has a conical front end that bears against the interior of conical flange 43. Packing sleeves 49 are of an elastic deformable material having a low coefficient of sliding friction, pref enably an elastomer and more preferably an organic elastomer, such as solid nylon, polytetrafiuoroethylene (Teflon) or polytrifluorochloroethylene (Kel-F), or the like. The sleeves 49 are backed up by an annular cylindrical metal collar 51.

Disposed between the sleeves 49 is a split valve body 53, comprised of a pair of identical valve halves 55. A gland nut 57 behind collar 51 is screw-threadedly engaged in barrel 41 and adjustably compresses the as sembly of sleeves 49 and collar 51 and valve body 53 within the interior of barrel 41. Gland nut 57 is tightened down on this assembly to the extent that packing sleeves 49 are placed in compression and are slightly deformed until a large portion of their internal diameter is smaller than the internal diameter of collar 51 and split valve body 53, and slightly less than the external diameter of the free end of plunger 15. The internal diameter of collar 51 and split valve body 53 is about the same as or only slightly greater than the external diameter of plunger so as slid-ably to receive plunger 15 with only that clearance necessary to facilitate smooth sliding of plunger 15 in these members.

The split valve body 53 has a cylindrical outer surface 59 and a cylindrical inner surface 61 that defines a portion of mixing chamber 37. The valve halves 55 fit together in complementary fashion to complete these cylindrical surfaces. In assembled relationship, the valve body 53 has annular radially extending end surfaces 63. Each valve half 55 has flat edge surfaces 65 and 67 which lie in parallel spaced planes. These planes are disposed equal distances on either side of the axis of valve body 53, these distances being less than the radius of valve body 53. The surface 65 of each valve half 55 is provided with a recess 69 therein. Each recess 69 opens upwardly and is of a length, measured parallel to the axis of valve body 53, which is at least several times greater than its depth measured peripherally of valve body 53. Preferably, these recesses are at least about five times as long as they are deep. In a particularly preferred embodiment, the recesses 69 are about ten times as long as they are deep.

In assembled relationship, the recess in one edge surface 65 is closed by the edge surface 67 of the other valve half 55. There are thus produced two inlet openings into mixing chamber 37, which register with the inlet openings 45 and 47 through barrel 41. The inlet openings 45 and 47, in turn, communicate separately with conduits 7 and 9, respectively, so that two liquids under pressure can be introduced from conduits 7 and and 9 through inlet openings 45 and 47 and thence through the inlet openings provided by recesses 69 into the interior of the mixing chamber. The inlet openings thus provided by recesses 69 are preferably not diametrically opposed to each other but are spaced from the axis of valve body 53 substantial distances which are nevertheless smaller than the radius of valve body 53.

The free end of plunger 15 is thus slidable from a position in which it is disposed within the rear packing sleeve 49, past the recesses 69 and through and past the front packing sleeve 49, to a position as shown in phantom line at the extreme right of FIGURE 2, in which the free end of plunger 15 protrudes slightly from outlet end 39 of mixing chamber 37. With sleeves 49 compressed so as to be slightly smaller in internal diameter than the external diameter of plunger 15, it will be appreciated that as plunger 15 moves through the sleeves 49, the sleeves 49 are slightly dilated by the intrusion of the free end of plunger 15. The free end of plunger 15 thus scours the passageway as it advances through the sleeves 49, and it has been found that this scouring action is effective to remove substantially all the mixed liquid from the passageway and to prevent cementing of the plunger in the passageway by the hardened mixture.

In operation, the user of the spray gun can actuate the device by depressing button 31, thereby opening valve 29 and causing piston 23 to move to the rear until the rear end of plunger 15 contacts plunger stop 35. In this position, which is the position of the parts shown in full line in FIGURE 2, the forward or free end of plunger 15 moves to the rear of recesses 69, and the different liquids that are supplied under pressure to conduits 7 and 9 rush into mixing chamber 37, where they are given a rotary or swirling movement by virtue of the offset of recesses 69 from each other. The mixing liquids thus move toward and out of outlet end 39 with a largely helical movement. The high kinetic energy of the stream may cause the stream to subdivide into discrete particles or drops. However, the fact that the outlet end of the mixing chamber is of the same diameter as the rest of the mixing chamber tends to make these drops rather larger than if outlet end 39 were reduced in diameter as is conventional.

When the operator releases button 31, compressed air to the forward side of piston 23 is cut off and spring 19 forces piston 23 forwardly until the piston contacts the front of its piston chamber. In this position, which is the position of the parts shown in FIGURE 1, and also the phantom line position of piston 15 as seen in FIGURE 2 the forward or free end of piston 15 occupies substantially all of outlet end 39 and preferably protrudes somewhat out of outlet end 39. By this forward movement of plunger 15, substantially all of the mixed liquid within chamber 37 is mechanically expelled. If the liquid is of the type that sets up into a relatively hard substance a short time after mixing, then the advantages of the present invention will be obvious in that substantially no mixed liquid will be left in chamber 37 to harden. On the other hand, the spray gun will be ready for use again and can is shown in FIGURE 5 of the drawing. As is there seen,

a valve housing 71 is provided, which includes a barrel 73 having a conical flange 75 as in the case of valve housing 5. Barrel 73 has a pair of spaced axially offset inlet openings 77 and 79 therethrough that can have the spacing described for inlet openings 45 and 47 of barrel 41. A sleeve 81 of the solid elastic deformable material described in connection with sleeves 49 is disposed in the internal cavity of barrel 73. The internal cylindrical surface of sleeve 81 and the radially innermost edge of conical flange 75 define a mixing chamber having the same configuration as mixing chamber 37. A gland nut 83 compresses sleeve 81 axially so as to deform sleeve 81 slightly into the cylindrical contour of its mixing chamher, The plunger 85 that reciprocates within this mixing chamber thus has an external diameter slightly larger than the radially inwardly deformed internal surface of sleeve 81. Sleeve 81 has inlet openings 87 and 89 that register respectively with inlet openings 77 and 79 of barrel 73, for the same purpose as in the embodiment of FIGURES 1-4. Inlet openings 87 and 89, however are provided through the material of sleeve 81 itself.

Apart from these differences, the function and mode of operation of the embodiment of FIGURE 5 are substantially the same as those of the embodiment of FIG- URES 1-4, and for the sake of brevity need not be repeated here.

Examples of formulations usable with the present spray gun to eject thermosetting resins are found in my patent identified above. Examples of suitable formulations of polyurethane foam-forming materials are found in US. Patents Nos. 2,921,866 and 3,004,934.

From a consideration of all of the foregoing, it will be obvious that I have achieved all of the initially recited objects of my invention.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit of the inven tion, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

Having described my invention, I claim:

1. Apparatus for ejecting a mixture of liquids, comprising means defining a mixing chamber having an open outlet end, means defining a plurality of spaced inlets opening into the chamber for separately introducing different liquids into the chamber, said inlets being spaced from said open outlet end, the chamber adjacent said inlets having an inside diameter substantially the same as said open outlet end, and a plunger reciprocable in said chamber, the plunger having a free end in sliding contact with the side walls of the chamber, the plunger being reciprocable rearwardly to a position in which said free end is disposed to the rear of said inlets and forwardly to a position in which said free end is disposed in said outlet opening.

2. Apparatus as claimed in claim 1, the side walls of the chamber being an elastic deformable material.

3. Apparatus as claimed in claim 2, said free end of the plunger being metal.

4. Apparatus as claimed in claim 3, said side walls having an internal diameter slightly less than the external diameter of the plunger when out of contact with the plunger,

5. Apparatus as claimed in claim 1, said chamber adjacent said inlets comprising at least a pair of elements having joints between them that extend lengthwise of the chamber, each of said inlets comprising a recess in the edge of one of said elements at a said joint.

6. Apparatus as claimed in claim 5, each of said recesses having a length at least several times greater than its depth.

7. Apparatus as claimed in claim 5, the edges of said elements at said joints being disposed in spaced parallel planes.

8. Apparatus as claimed in claim 1, said inlets having a length parallel to the length of the chamber which is substantially greater than their width peripherally of the chamber.

9. Apparatus for ejecting mixed liquids, comprising means defining a mixing chamber having an open outlet end, means defining a plurality of spaced inlets opening into the chamber for separately introducing different liquids into the chamber, said inlets being spaced from said open outlet end, said inlets having a length parallel to the length of the chamber which is substantially greater than their width peripherally of the chamber, and a plunger reciprocable in said chamber to open and close said inlets.

10. Apparatus for ejecting mixed liquids, comprising means defining a mixing chamber having an open outlet end, means defining a pluralityof spaced inlets opening into the chamber for separately introducing different liquids into the chamber, said inlets being spaced from said open outlet end, said chamber adjacent said inlets comprising at least a pair of elements having joints between them that extend lengthwise of the chamber, each of said inlets comprising a recess in the edge of one of said ele ments at a said joint, and a plunger reciprocable in said chamber to open and close said inlets.

11. Apparatus as claimed in claim 10, each of said recesses having a length at least several times greater than its depth.

12. Apparatus as claimed in claim 10, the edges of said elements at said joints being disposed in spaced parallel planes.

References Cited by the Examiner UNITED STATES PATENTS 3,105,616 10/1963 Krup 222- X 3,111,271 11/1963 Lofgren 239117 X ROBERT B. REEVES, Primary Examiner. HADD S. LANE, Examiner. 

1. APPARATUS FOR EJECTING A MIXTURE OF LIQUIDS, COMPRISING MEANS DEFINING A MIXING CHAMBER HAVING AN OPEN OUTLET END, MEANS DEFINING A PLURALITY OF SPACED INLETS OPENING INTO THE CHAMBER FOR SEPARATELY INTRODUCING DIFFERENT LIQUIDS INTO THE CHAMBER, SAID INLETS BEING SPACED FROM SAID OPEN OUTLET END, THE CHAMBER ADJACENT SAID INLETS HAVING AN INSIDE DIAMETER SUBSTANTIALLY THE SAME AS SAID OPEN OUTLET END, AND A PLUNGER RECIPROCABLE IN SAID CHAMBER, THE PLUNGER HAVING A FREE END IN SLIDING CONTACT WITH THE SIDE WALLS OF THE CHAMBER, THE PLUNGER BEING RECIPROCABLE REARWARDLY TO A POSITION IN WHICH SAID FREE END IS DISPOSED TO THE REAR OF SAID INLETS AND FORWARDLY TO A POSITION IN WHICH SAID FREE END IS DISPOSED IN SAID OUTLET OPENING. 